chore(deps): Update actions/upload-artifact action to v6

Author: cq-bot

.github/workflows/unittest.yml

@@ -36,7 +36,7 @@ jobs:
         run: echo ${{ github.event.number }} > ./pr_number
       - name: Upload deltas
         if: matrix.os == 'ubicloud-standard-8'
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: delta-action-benchmarks
           retention-days: 7